init interpreter

src/frontend/token.zig

@@ -51,14 +51,16 @@ fn is_op(c: u8) bool {
     };
 }
 
-pub fn op_kind(op: []const u8) TokenKind {
-    const v: u16 = switch (op.len) {
+pub fn op_val(op: []const u8) u16 {
+    return switch (op.len) {
         1 => op_map[op[0]],
         2 => op_map[op[0]] + (@as(u16, op_map[op[1]]) << 5),
         3 => op_map[op[0]] + (@as(u16, op_map[op[1]]) << 5) + (@as(u16, op_map[op[2]]) << 10),
         else => @intFromEnum(TokenKind.invalid),
     };
-    return @enumFromInt(v);
+}
+pub fn op_kind(op: []const u8) TokenKind {
+    return @enumFromInt(op_val(op));
 }
 
 const Operator = @import("parse.zig").Operator;

src/interp/compile.zig

@@ -0,0 +1,74 @@
+const std = @import("std");
+const parse = @import("../frontend/parse.zig");
+const Expr = parse.Expr;
+
+pub const sz_tag = enum {
+    int,
+    num,
+    bool,
+    str,
+    list,
+    err,
+};
+pub const sz_obj = struct {
+    obj: usize = 0,
+    obj2: usize = 0,
+    tag: sz_tag = .int,
+};
+
+pub const sz_inst = union(enum) {
+    push_const: u16,
+    push_var: u16,
+    pop,
+    pop_var: u16,
+    binop: u16,
+    unop: u16,
+    jump: u16,
+    ret,
+};
+pub const sz_code = struct {
+    consts: []sz_obj,
+    vars: []sz_obj,
+    bc: []sz_inst,
+};
+const sz_code_tmp = struct {
+    consts: std.ArrayList(sz_obj),
+    vars: std.ArrayList(sz_obj),
+    bc: std.ArrayList(sz_inst),
+    fn finalize(self: *sz_code_tmp) !sz_code {
+        return sz_code{
+            .consts = try self.consts.toOwnedSlice(),
+            .vars = try self.vars.toOwnedSlice(),
+            .bc = try self.bc.toOwnedSlice(),
+        };
+    }
+    fn append(self: *sz_code_tmp, src: []const u8, expr: *const Expr) !void {
+        switch (expr.*) {
+            .atom => |a| {
+                switch (a.kind) {
+                    .number => try self.consts.append(.{ .obj = @bitCast(std.fmt.parseInt(isize, src[a.start..a.end], 0) catch 0) }),
+                    else => unreachable,
+                }
+                try self.bc.append(.{ .push_const = @truncate(self.consts.items.len - 1) });
+            },
+            .binop => |b| {
+                try self.append(src, b.lhs);
+                try self.append(src, b.rhs);
+                try self.bc.append(.{ .binop = @intFromEnum(b.op.kind) });
+            },
+            .unop => |u| {
+                try self.append(src, u.expr);
+                try self.bc.append(.{ .unop = @intFromEnum(u.op.kind) });
+            },
+        }
+    }
+};
+
+pub fn compile(allocator: std.mem.Allocator, src: []const u8) !sz_code {
+    var p = try parse.Parser.init(allocator);
+    const expr = try p.parse(src);
+    var code = sz_code_tmp{ .consts = std.ArrayList(sz_obj).init(allocator), .vars = std.ArrayList(sz_obj).init(allocator), .bc = std.ArrayList(sz_inst).init(allocator) };
+    try code.append(src, expr);
+    try code.bc.append(.{ .pop = {} });
+    return code.finalize();
+}

src/interp/vm.zig

@@ -0,0 +1,140 @@
+const std = @import("std");
+const op_val = @import("../frontend/token.zig").op_val;
+
+const compile = @import("compile.zig");
+const sz_tag = compile.sz_tag;
+const sz_inst = compile.sz_inst;
+const sz_code = compile.sz_code;
+const sz_obj = compile.sz_obj;
+
+pub const sz_vm = struct {
+    code: sz_code,
+    stack: std.ArrayList(sz_obj),
+    allocator: std.mem.Allocator,
+    pc: usize,
+    pub fn init(allocator: std.mem.Allocator, code: sz_code) sz_vm {
+        return sz_vm{ .code = code, .stack = std.ArrayList(sz_obj).init(allocator), .allocator = allocator, .pc = 0 };
+    }
+    pub fn step(self: *sz_vm) !void {
+        const inst = self.code.bc[self.pc];
+        switch (inst) {
+            .push_const => |i| try self.stack.append(self.code.consts[i]),
+            .push_var => |i| try self.stack.append(self.code.vars[i]),
+            .pop => {
+                const a = self.stack.pop().?;
+                switch (a.tag) {
+                    .int => std.debug.print("{}\n", .{a.obj}),
+                    .num => std.debug.print("{}\n", .{@as(f64, @bitCast(a.obj))}),
+                    .str => std.debug.print("{s}\n", .{@as([*]u8, @ptrFromInt(a.obj))[0..a.obj2]}),
+                    else => {},
+                }
+            },
+            .pop_var => |i| self.code.vars[i] = self.stack.pop().?,
+            .binop => |i| {
+                const rhs = self.stack.pop().?;
+                const lhs = self.stack.pop().?;
+                try self.stack.append(try self.binop(lhs, rhs, i));
+            },
+            .unop => |i| try self.stack.append(self.unop(self.stack.pop().?, i)),
+            else => unreachable,
+        }
+        self.pc += 1;
+    }
+    fn binop(self: *sz_vm, lhs: sz_obj, rhs: sz_obj, op: u16) !sz_obj {
+        if (lhs.tag == rhs.tag) {
+            switch (lhs.tag) {
+                .int => {
+                    const lo: isize = @bitCast(lhs.obj);
+                    const ro: isize = @bitCast(rhs.obj);
+                    const obj = switch (op) {
+                        op_val("+") => lo + ro,
+                        op_val("-") => lo - ro,
+                        op_val("*") => lo * ro,
+                        op_val("/") => @divFloor(lo, ro),
+                        else => return .{ .tag = .err },
+                    };
+                    return .{ .obj = @bitCast(obj) };
+                },
+                .num => {
+                    const lo: f64 = @bitCast(lhs.obj);
+                    const ro: f64 = @bitCast(rhs.obj);
+                    const obj: f64 = switch (op) {
+                        op_val("+") => lo + ro,
+                        op_val("-") => lo - ro,
+                        op_val("*") => lo * ro,
+                        op_val("/") => lo / ro,
+                        else => return .{ .tag = .err },
+                    };
+                    return .{ .tag = .num, .obj = @bitCast(obj) };
+                },
+                .bool => {
+                    const lo = lhs.obj != 0;
+                    const ro = rhs.obj != 0;
+                    const obj: u64 = switch (op) {
+                        op_val("&&") => if (lo and ro) 1 else 0,
+                        op_val("||") => if (lo or ro) 1 else 0,
+                        else => return .{ .tag = .err },
+                    };
+                    return .{ .tag = .num, .obj = obj };
+                },
+                .str => {
+                    const lo = @as([*]u8, @ptrFromInt(lhs.obj))[0..lhs.obj2];
+                    const ro = @as([*]u8, @ptrFromInt(rhs.obj))[0..rhs.obj2];
+                    const obj = switch (op) {
+                        op_val("+") => try std.mem.concat(self.allocator, u8, &[_][]u8{ lo, ro }),
+                        else => return .{ .tag = .err },
+                    };
+                    return .{ .tag = .str, .obj = @intFromPtr(obj.ptr), .obj2 = lhs.obj2 + rhs.obj2 };
+                },
+                .list => {
+                    const lo = @as([*]sz_obj, @ptrFromInt(lhs.obj))[0..lhs.obj2];
+                    const ro = @as([*]sz_obj, @ptrFromInt(rhs.obj))[0..rhs.obj2];
+                    const obj = switch (op) {
+                        op_val("+") => try std.mem.concat(self.allocator, sz_obj, &[_][]sz_obj{ lo, ro }),
+                        else => return .{ .tag = .err },
+                    };
+                    return .{ .tag = .list, .obj = @intFromPtr(obj.ptr), .obj2 = lhs.obj2 + rhs.obj2 };
+                },
+                .err => return lhs,
+            }
+        }
+        return switch (op) {
+            op_val("*") => switch (lhs.tag) {
+                .int => switch (rhs.tag) {
+                    .str => .{ .tag = .str, .obj = @intFromPtr((try mul_slice(self.allocator, u8, @as([*]u8, @ptrFromInt(rhs.obj))[0..rhs.obj2], lhs.obj)).ptr), .obj2 = rhs.obj2 * lhs.obj },
+                    .list => .{ .tag = .list, .obj = @intFromPtr((try mul_slice(self.allocator, sz_obj, @as([*]sz_obj, @ptrFromInt(rhs.obj))[0..rhs.obj2], lhs.obj)).ptr), .obj2 = rhs.obj2 * lhs.obj },
+                    else => .{ .tag = .err },
+                },
+                .str => switch (rhs.tag) {
+                    .int => .{ .tag = .str, .obj = @intFromPtr((try mul_slice(self.allocator, u8, @as([*]u8, @ptrFromInt(lhs.obj))[0..lhs.obj2], rhs.obj)).ptr), .obj2 = lhs.obj2 * rhs.obj },
+                    else => .{ .tag = .err },
+                },
+                .list => switch (rhs.tag) {
+                    .int => .{ .tag = .list, .obj = @intFromPtr((try mul_slice(self.allocator, sz_obj, @as([*]sz_obj, @ptrFromInt(lhs.obj))[0..lhs.obj2], rhs.obj)).ptr), .obj2 = lhs.obj2 * rhs.obj },
+                    else => .{ .tag = .err },
+                },
+                else => .{ .tag = .err },
+            },
+            else => .{ .tag = .err },
+        };
+    }
+    fn unop(self: sz_vm, obj: sz_obj, op: u16) sz_obj {
+        _ = self;
+        return switch (obj.tag) {
+            .int => switch (op) {
+                op_val("+") => obj,
+                op_val("-") => .{ .obj = ~obj.obj + 1 },
+                else => .{ .tag = .err },
+            },
+            else => .{ .tag = .err },
+        };
+    }
+};
+
+fn mul_slice(allocator: std.mem.Allocator, comptime T: type, slice: []T, n: usize) ![]T {
+    var m = try allocator.alloc(T, slice.len * n);
+    for (0..n) |i| {
+        @memcpy(m[i * slice.len .. (i + 1) * slice.len], slice);
+    }
+    return m;
+}

src/main.zig

@@ -18,9 +18,16 @@ pub fn main() !void {
     const content = try file.readToEndAlloc(allocator, std.math.maxInt(usize));
     defer allocator.free(content);
 
-    var p = try lib.parse.Parser.init(allocator);
-    defer p.free();
-    std.debug.print("{}\n", .{(try p.parse(content)).eval(content)});
+    const code = try lib.compile.compile(allocator, content);
+    std.debug.print("{any}\n", .{code.bc});
+    var vm = lib.vm.sz_vm.init(allocator, code);
+    while (true) {
+        try vm.step();
+        for (vm.stack.items) |i| {
+            std.debug.print("{} ", .{i.obj});
+        }
+        std.debug.print("\n", .{});
+    }
 }
 
 test {

src/root.zig

@@ -1,6 +1,8 @@
 const std = @import("std");
 pub const token = @import("frontend/token.zig");
 pub const parse = @import("frontend/parse.zig");
+pub const vm = @import("interp/vm.zig");
+pub const compile = @import("interp/compile.zig");
 
 test {
     std.testing.refAllDecls(@This());